JP3156000B2 - Error detection code generation line controller - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an error detection code generation line controller for detecting an error in data in a storage and switching network and generating an error detection code.

[0002]

2. Description of the Related Art Conventionally, in a data error detection system in a storage and switching network (hereinafter, switching network), data errors are detected end-to-end in the switching network. A check code is added to a part of the data and the data is collated to detect a data error in the switching network.

[0003]

The switching network as described above,
For example, X. In the switching network, the data error of the level 4 or higher, which is the portion where the switching network does not change the data content, can be guarded. It is not possible to guard against data errors in the level 3 header, level 3 call setting information, and in-network header that are replaced or changed in a 25 switch or the like. Therefore, the present invention provides Level 3
An object of the present invention is to generate an error detection code for the entire header of the level 3 header for the header portion and individually for the level 3 call setting information, thereby performing error detection for all data.

[0004]

In order to solve such a problem, the present invention divides each data content control procedure layer or the same control procedure layer into a plurality of parts when receiving data from a subscriber terminal. A means for generating an error detection code for data for each element, inserting and attaching each to each data or at the tail of each data, and generating an error detection code at the time of data transmission to the subscriber terminal and collating it with the transmitted data If the transmission data is correct, the transmission data is sent to the subscriber terminal as it is, and if an error is detected in the transmission data, the transmission data is discarded, or data such that the transmission data is discarded by the subscriber terminal is added to the transmission data. Means provided in the line control device in the exchange.

[0005]

When receiving data from a subscriber terminal, the line controller in the exchange creates and adds an error detection code for each layer or for each element obtained by dividing the same control procedure layer into a plurality of parts. When sending data to the subscriber terminal, an error detection code is generated in the same way as when receiving data, and when it is confirmed that the data is correct, the data is sent to the subscriber terminal normally and the data abnormality is detected. When detected, abnormal data is added to the transmission data and transmitted so that the data is discarded or the transmission data is discarded at the subscriber terminal. As a result, it is possible to detect and eliminate the occurrence of data errors in the switching network.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing an embodiment of a system to which an error detection code generation line controller according to the present invention is applied. This system shows an example of a switching network composed of two terminals and three switches. ing. In FIG. 1, 100
To 105 are line controllers, 200 to 202 are exchanges, 2
10 to 212 are exchange control devices, 220 to 222 are exchange memories, 300 and 303 are subscriber lines, and 301 and 30.
2 is a trunk line, and 400 and 401 are terminals. In FIG. 1, it is assumed that a level 2 procedure and a level 3 procedure of the data control procedure hierarchy are supported between the terminal and the exchange, and a level 2 procedure is supported between the exchanges.

Next, FIG. 2 is an explanatory diagram showing data on a line. In the figure, reference numerals 1 and 3 denote data on a line, and 2
Is data on the memory, 500 and 502 are level 2 headers, 501 and 503 are level 2 trailers, 600 and 60
2 is a level 3 header, 601 and 603 are level 3 error detection check codes, 700 is level 4 or higher data,
Reference numeral 701 denotes a data error detection check code of level 4 or higher.

Here, the operation of the apparatus of this embodiment will be described with reference to FIGS. When terminal 400 sends data 1 to subscriber line 300, line control device 1 of exchange 200
00 is the level 2 header 500 and the level 2 trailer 50
1 to confirm the normality of the data 1, and an error detection check code 601 corresponding to the contents of the level 3 header 600 and an error detection check code 701 corresponding to the contents of the data 700 at the level 4 or higher. It is attached to the back and transferred to the exchange memory 220. As a result, the data on the memory has a form as shown in FIG.

The exchange 200 exchanges data 2 in the memory. At this time, the level 3 header 600 is changed to a level 3 header 602 as a processing result. For this reason, the check code 601 for error detection is also re-created to be the check code 603 for level 3 error detection. Therefore, the trunk line 30 when transferred to the destination exchange 202
The data on 1302 is in the form shown in FIG.

The data on such a trunk line is transferred to the exchange 2
02 transmits to the terminal 401, the exchange 200
The line control device 100 performs the same processing as when receiving data from the subscriber line 300. That is, when sending the level 3 header to the terminal 401 via the subscriber line 303, the line control unit 105 in the exchange 202 checks for errors in the received data contents on the trunk line for error detection. Write and evaluate code. If this is correct, the check code is deleted and the sending process is continued, and if the received data is incorrect and the received error detection check code does not match the created check code, the received data is discarded or being sent. Is discarded by the level 2 procedure. If the data 700 of level 4 or higher is normal, a level 2 trailer is created based on the level 3 header 602 and the data 700 of level 4 or higher according to the level 2 procedure, and the terminal 4
Send to 01. With the above processing, it is possible to prevent the mixing of erroneous data between the end and the end of the switching network.

FIG. 3 is a diagram showing a second embodiment of the present invention, and is an explanatory diagram showing data on a line at this time. In the figure, 4 and 6 are data on a line, 5 is data on a memory, 500 and 502 are level 2 headers, 50
1,503 is a level 2 trailer, 600,610,61
2 is two element data in the level 3 header, 601, 6
11 and 613 are two element data 6 in the level 3 header
Level 3 error detection check codes corresponding to 00, 610, 612, 700 is level 4 or higher data, 701
Is a check code for error detection of data of level 4 or higher. 610 is a kind of data whose contents change in the originating exchange.

Next, the operation of the second embodiment of the present invention will be described with reference to FIGS. First, the terminal 400 is connected to the line 30
When the data 4 is transmitted to the switch 0, the line control unit 100 of the exchange 200 sends the level 2 header 500 and the level 2 trailer 5
01 to confirm the normality of Data 1 and Level 3
Check codes 601 and 611 for error detection corresponding to the contents of the headers 600 and 610 and data of level 4 or higher 7
Error detection check code 701 corresponding to 00
Is appended to each data and transferred to the memory 220. In this case, the data 5 on the memory has a form as shown in FIG.

Here, the exchange 200 exchanges data on the memory. At this time, the level 3 header 600
Is unchanged, but the data 610 becomes the data 612 with the change, and the check code for error detection is calculated and reset to become the check code 613. Therefore, the data 6 on the trunk line at the time of transfer to the destination exchange 202 has a form as shown in FIG.

When the exchange 202 transmits data to the terminal 401, the same processing as when the line control unit 100 in the exchange 200 receives data from the terminal 400 via the subscriber line 300 is performed. That is, when the line control unit 105 in the exchange 202 transmits the level 3 header, an error detection check code is created and compared to confirm that there is no error in the data contents. If they match, the check code is deleted and transmission is continued. If they do not match, the data being transmitted is discarded by the level 2 procedure. Then, when the data is normal, the data 700 of the level 4 or higher is transmitted, and the level 3 header 600
Confirm the normality of this as well. As a result, if the data 700 of level 4 or higher is also normal, the level 3 header 600 and the data 70 of level 4 or higher follow the level 2 procedure.
A level 2 trailer is created based on 0 and sent to the terminal 401. With the above processing, it is possible to prevent mixing of error data between the end and the end of the switching network.

As described above, when data is received from the subscriber terminal, an error detection code is generated by the line controller for each level, that is, for each layer, or for each element obtained by dividing the same control procedure layer into a plurality of parts. To add. Thereafter, the originating exchange exchanges the multiplexing identifiers (logical channels, DLCI, VPI, etc.) of the multiplexing layer and exchanges such as data deletion for each layer used only by the originating exchange to deliver the received data to the destination subscriber. At this time, the line control device adds an error detection check code to each layer or each element divided into a plurality of parts even in the same layer. For this reason, deletion only needs to be performed for each element, and when it is changed, only the change of the changed portion and the calculation and setting of the check code accompanying the change are required. Also, when the line controller of the destination exchange sends data to the subscriber terminal, it generates an error detection code in the same way as when it was added when receiving data from the subscriber terminal, and confirmed that the received data was correct. When this is done, the data is normally transmitted to the subscriber as it is, and when an abnormality in the received data is detected, the data is discarded or abnormal data is added to the transmitted data so that the subscriber terminal can discard the transmitted data. As a result,
The occurrence of data errors in the switching network can be detected and excluded, and a high-quality switching network can be constructed.

[0016]

As described above, according to the present invention, an error detection code is created and added by a line control unit in an exchange for each layer or for each element of a variable length layer, and the line control unit At the time of data transmission, an error detection code is created in the same way as when it was added at the time of data reception, and when it is confirmed that the transmission data is the same, it is transmitted to the subscriber as it is, and when an abnormality is detected, the subscription is made. By adding an abnormal indication to the outgoing data so that the outgoing data can be discarded at the user terminal, the occurrence of data errors in the switching network can be detected and eliminated, and therefore, a high-quality switching network can be constructed. it can.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of a system to which an error detection code generation channel control device according to the present invention is applied.

FIG. 2 is an explanatory diagram showing data on a line in the system.

FIG. 3 is an explanatory diagram showing data on a line in the system.

[Explanation of symbols]

1,3,4,6 Data on line 2,5 Data on memory 100-105 Line controller 200-202 Switch 210-212 Switch controller 220-222 Switch memory 300,303 Subscriber line 301,302 Trunk line 400, 401 Terminal 500, 502 Level 2 header 501, 503 Level 2 trailer 600, 602 Level 3 header 601, 603 Level 3 error detection check code 700 Level 4 or higher data 701 Level 4 or higher data error detection check code

Continuation of the front page (72) Inventor Minoru Tanaka 1-1-6 Uchisaiwaicho, Chiyoda-ku, Tokyo Nippon Telegraph and Telephone Corporation (72) Hidenori Takahashi 1-1-6 Uchisaiwaicho, Chiyoda-ku, Tokyo Nippon Telegraph and Telephone Inside (72) Inventor Seiji Togo 1-1-6 Uchisaiwaicho, Chiyoda-ku, Tokyo Nippon Telegraph and Telephone Corporation (72) Inventor Hidetoshi Saigo 1-1-6 Uchisaiwaicho, Chiyoda-ku, Tokyo Nippon Telegraph and Telephone Corporation (72) Inventor Hideo Shinoda 1-1-6 Uchisaiwai-cho, Chiyoda-ku, Tokyo Nippon Telegraph and Telephone Corporation (72) Inventor Shoji Kanae 1-6-6 Uchisaiwai-cho, Chiyoda-ku, Tokyo Nippon Telegraph and Telephone Corporation (56) References JP-A-58-127450 (JP, A) JP-A-59-188253 (JP, A) JP-A-4-160954 (JP, A) (58) Fields investigated (Int. ⁷ , DB name) H04L 12/28 H04L 12/56

Claims (1)

(57) [Claims] 1. A storage and switching network comprising a plurality of exchanges accommodating a subscriber line and a trunk line, for controlling a subscriber terminal through the subscriber line and for controlling the subscriber terminal in the storage and switching network. A line control device for detecting occurrence of data error, which is used to detect data errors for each control procedure layer of data contents or for each element obtained by dividing the same control procedure layer into a plurality of parts when receiving data from the subscriber terminal. Means for generating codes and inserting and adding the codes to each data or each data tail, and generating an error detection code at the time of data transmission to the subscriber terminal, collating the codes with the transmitted data, and checking whether the transmitted data is erroneous. If not, send the data to the subscriber terminal as it is, and discard the transmitted data when an abnormality is detected in the transmitted data, or discard the transmitted data by the subscriber terminal. Means for adding error detection code to transmission data.